Structures utilizing phase change for heat management applications

Abstract

An article is described that comprises a reticulated foam structure comprising a first ceramic or metal composition, and a second ceramic or metal composition disposed within the reticulated foam structure. The article may be compressed and sintered to form a monolith that can be used for mange heat by consuming heat energy through a phase change of one of the compositions.

Having thus described the invention, it is claimed: 
     
       1. A method, comprising:
 providing a reticulated foam structure comprising a first ceramic or metal composition; 
 loading particles comprising a second ceramic or metal composition into spaces in the reticulated foam structure; and 
 compressing and heating the reticulated foam structure having the particles loaded therein to sinter and form a monolithic structure; 
 wherein one of the first ceramic or metal composition or second ceramic or metal composition is selected from the group consisting of TaC, Ta 2 C, and combinations thereof, and other of the first ceramic or metal composition or second ceramic or metal composition is selected from the group consisting of B 4 C, SiC, and combinations thereof. 
 
     
     
       2. The method of  claim 1 , wherein the providing of the reticulated foam structure comprising the first ceramic or metal composition comprises:
 providing a reticulated polymer foam structure; 
 coating the reticulated polymer foam structure with a slurry of particles comprising the first ceramic or metal composition or vapor depositing a layer of the first ceramic or metal composition onto the reticulated polymer foam structure; and 
 heating the reticulated polymer foam structure coated with particles comprising the first ceramic or metal composition at a temperature and for a time sufficient to pyrolyze the polymer and, if the polymer foam structure was coated with a slurry of particles, sufficient to sinter the slurry particles. 
 
     
     
       3. The method of  claim 1 , wherein one of the first or second ceramic or metal compositions remains a solid at temperatures below a phase change temperature threshold, and the other of the first or second ceramic or metal compositions exhibits a phase change from solid to either liquid or vapor at a temperature below the phase change temperature threshold. 
     
     
       4. The method of  claim 3 , further comprising exposing the structure to heat from a heat source sufficient to cause a phase change of said composition that exhibits a phase change from solid to either liquid or vapor at a temperature below the phase change temperature threshold without causing a phase change of the other of said first or second compositions, such that heat energy from the heat source is thereby consumed by the phase change. 
     
     
       5. A method of managing heat, comprising:
 providing an article comprising a first ceramic composition and a second ceramic or metal composition, wherein one of the first or second compositions remains a solid at temperatures below a phase change temperature threshold, the other of the first or second compositions exhibits a phase change from solid to either liquid or vapor at a temperature below the phase change temperature threshold, the composition that remains a solid at temperatures below the phase change temperature threshold is selected from the group consisting of TaC, Ta 2 C, and combinations thereof, and the composition that exhibits a phase change from solid to either liquid or vapor at a temperature below the phase change temperature threshold is selected from the group consisting of B 4 C, SiC, and combinations thereof; and 
 exposing the article to heat from a heat source sufficient to cause a phase change of said composition that exhibits a phase change from solid to either liquid or vapor at a temperature below the phase change temperature threshold without causing a phase change of the other of said first or second compositions, such that heat energy from the heat source is thereby consumed by the phase change. 
 
     
     
       6. The method of  claim 5 , wherein the phase change temperature threshold is about 2700° C. 
     
     
       7. The method of  claim 5 , wherein one of the first or second compositions remains a solid up to a temperature of at least about 3000° C., and the other of the first or second compositions exhibits a phase change from solid to either liquid or vapor at a temperature below about 2500° C. 
     
     
       8. The method of  claim 5 , wherein the composition that exhibits a phase change from solid to either liquid or vapor below the phase change temperature threshold has a phase change enthalpy of at least 10 kJ/g. 
     
     
       9. The method of  claim 5 , wherein the providing of the article comprises:
 providing a reticulated foam structure comprising the first ceramic composition; 
 loading particles comprising the second ceramic or metal composition into spaces in the reticulated foam structure; and 
 compressing and heating the reticulated foam structure having the particles loaded therein to sinter and form the article. 
 
     
     
       10. The method of  claim 5 , wherein the providing of the article comprises:
 providing a reticulated foam structure comprising the second ceramic or metal composition; 
 loading particles comprising the first ceramic composition into spaces in the reticulated foam structure; and 
 compressing and heating the reticulated foam structure having the particles loaded therein to sinter and form the article.